I have a hinged bangle which has a spring at the hinged joint. The
spring has broken and I am trying to replace it. I ordered an
assortment from a watch part supplier but all are too wide. I heated
one of them and unraveled it so that it would fit the space but when
I tried to re-temper the spring it stayed annealed. I heated the
spring to red heat and quenched it. Anyone out there know the proper
method to re-harden a spring? Also would anyone have a source for
small springs suitable for catches and other jewellery uses?

Here is a tip I learned from Mr. Revere, (sometimes the old fella
has some good ideas). Go to your local music store and get a guitar
string and you can make your own springs any size you like. Most
stores sell individual strings, ask for one of the first 3 high
strings and choose the best gauge to fit your needs.

I have a hinged bangle which has a spring at the hinged joint.
The spring has broken and I am trying to replace it. I ordered an R
Hood

Hi R; Tempering a spring, especially a small one, is a tricky
proposition. I’d call a few music stores and see if they have any
"piano wire" of the right gauge. Sometimes, you can use piano wire
and simply bend it around without having to temper it. Spring steel
is a high-carbon steel. And spring steel wire is not easy to come
by. I’m afraid I don’t know a source, but a gunsmith might know.
The process of tempering involves the following steps:

1. annealing.
2. shaping.
3. hardening.
4. tempering.

Don’t heat the spring directly with the torch. Put it on a piece of
metal, copper or steel or other, and heat the metal from beneath.
Heat it till the spring is a red heat, then allow it to cool slowly
as follows: When it’s red hot, leave it on the metal and let metal,
spring and all cool slowly. This anneals the spring. After it
cools, shape the spring. Then, heat the spring, again using the
piece of metal, to a red heat and drop it in a small container of
oil. At this point, the spring is too hard. Don’t try bending it
now or you’ll break it. You will now anneal it back to the proper
temper as follows: Clean off all the discoloration till it’s bright,
clean metal, either by sanding, sand-blasting, or otherwise abrading.
Doesn’t have to be perfect, just clean enough to see the oxide
colors that will form when you heat it again to temper it. Put the
clean spring on the piece of metal, heat from the bottom, and when
the spring turns peacock blue, immediately drop it in a container of
oil. Gently test it by seeing if it bends. If it feels too stiff,
don’t force it or you’ll break it If this makes the spring too
stiff, you’ll have to temper it using oil that is kept hot. If the
spring is too soft, meaning that it doesn’t return to it’s shape,
you’ll have to adjust it back in shape and go through the process of
hardening it and tempering it again, but this time, don’t let it get
all the way to the peacock blue in the final heating, but rather stop
it at a straw-yellow color (yellow turning into brown). There are
many variations on this tempering method, and a little research might
turn up one that is a little more understandable than mine. It’s the
same process used to temper any steel tool, except that the tempering
colors are going to need to be appropriate for the high-carbon spring
steel.

Go back to the watch supply and ask for springwire in the gauge that
you need. Then wrap the spring into the size and shape that you need.
Do not try to anneal or temper it It is fine for making springs as it
is. It can be drawn down in a steel drawplate, but do not try to draw
it down in a carbide drawplate, as it WILL break the dies.

Hi, Spring wire is available from Mcmastercarr catalog in small
spools . The best is their stainless steel springwire… It won’t
rust in your jewelry applications. Daniel Grandi
Racecar Jewelry Co. Inc.